1. Field of the Invention
The present invention relates to an information recording medium, such as an optical disc or the like, an information recording apparatus for recording record information onto the information recording medium, and an information reproducing apparatus for reproducing the record information recorded on the information recording medium. More particularly, it relates to an information recording medium on which reproduction control information to control a reproduction of the recorded record information is recorded together with the record information, an information recording apparatus for recording the reproduction control information together with the record information onto the information recording medium, and an information reproducing apparatus for reproducing the record information recorded on the information recording medium.
2. Description of the Related Art
In recent years, a technique has been developed, which increases a recording capacity on an information recording medium such as an optical disc or the like and records one entire movie on one sheet of optical disc for example. As a result, a so-called DVD having a recording capacity equal to about seven times as that of a conventional CD (Compact Disc) is put into a practical use.
Then, as this DVD, in addition to a so-called DVD video to record the above-mentioned movie, a so-called DVD audio to record only voice information and tone information other than voice information such as accompaniment information and the like is also put into a practical use (hereafter, the voice information and the tone information are collectively referred to as xe2x80x9caudio informationxe2x80x9d).
However, in a conventionally-developed DVD audio, there may be a case that the audio information to be recorded onto the DVD audio (in other words, a disc recorded in a DVD audio format) is non-compressed audio information, for example, such as a so-called PCM (Pulse Code Modulation) and the like. In this case, the non-compression causes the drop of an information amount which can be recorded on one sheet of DVD audio. Thus, this case brings about a problem of a result opposite to tendency of high density.
If a conventionally typical audio information compression method (for example, a so-called MPEG (Moving Picture Experts Group) method and the like) is used as it is to record the compressed audio information onto a DVD audio, since this method is carried out in a non-reversible compression, this brings about a problem of a quality drop of the reproduced audio information.
The compression method and the record format of the DVD audio are integrated inseparably, in many cases. Thus, when reproducing the compressed audio information, it is always required to carry out an operation of detecting the compressed audio information based on the DVD audio record format from the DVD audio and an operation of expanding or decompressing (which is an inversion of compressing) and demodulating or decoding the detected compressed audio information by using a single information reproducing apparatus. Hence, this results in the following problems. That is, it is very difficult to reproduce the audio information at a higher quality as a whole by respectively carrying out the detecting operation and the recovering and demodulating operation by using individual information reproducing apparatuses. Also, a flexibility in a configuration of the information reproducing apparatus is lost.
It is therefore an object of the present invention to provide an information recording medium, on which raw audio information in a long time duration can be recorded while keeping its original quality in an DVD audio format and which can allow a flexible selection in a structure of an information reproducing apparatus for reproducing the compressed audio information therefrom, and an information recording apparatus for recording the compressed audio information onto the information recording medium, and an information reproducing apparatus for reproducing the compressed audio information recorded on the information recording medium.
The above object of the present invention can be achieved by an information recording medium such as a DVD audio or the like on which record information is recorded, the record information comprising a plurality of information units each including header information and divided-compressed audio information obtained by dividing compressed audio information so as to include one or a plurality of lead data positioned at a lead of compressed partial audio information, the compressed partial audio information being generated by variable-length-compressing partial audio information obtained by dividing raw audio information into a plurality of the partial audio information and by multiplexing the variable-length-compressed partial audio information with compression control information, the compressed audio information being generated by arranging the compressed partial audio information in an order of reproduction. The compression control information includes first control information to control an inputting and outputting operation of the compressed partial audio information with respect to a first buffer, which is used when reproducing the compressed audio information. The header information includes second control information to control an inputting and outputting operation of the divided-compressed audio information with respect to a second buffer, which is used when reproducing the compressed audio information.
According to the information recording medium of the present invention, since the raw audio information is recorded after it is variable-length-compressed, it is possible to record even the raw audio information, whose reproduction time is long, onto the information recording medium.
Therefore, it is possible to record the audio information of long time duration as compared with a case of recording the non-compressed audio information onto the information recording medium.
Further, since the first control information, which is to control the inputting and outputting operation of the compressed partial audio information with respect the first buffer, is included in the compression control information, and since the second control information, which is to control the inputting and outputting operation of the divided-compressed audio information with respect to the second buffer, is included in the header information, it is possible at the time of reproducing the compressed audio information to easily perform (i) the operation of detecting the compressed audio information from the information recording medium and (ii) the operation of expanding or decompressing the detected compressed audio information by respectively using the first control information and the second control information individually, even if those two operations are performed by individual information reproducing apparatuses, each of which has just one of the first buffer and the second buffer.
Therefore, it is possible to easily promote the cost reduction and the simplification in the structure of the information reproducing apparatus, by performing the detection of the compressed audio information and the decoding process (e.g., expanding or decompressing, and demodulating processes) by use of the individual information reproducing apparatuses.
In one aspect of the information recording medium of the present invention, the first control information comprises: first input time information multiplexed for each of all the compressed partial audio information and indicating a time on a reproduction time axis of the compressed audio information when the compressed partial audio information, to which the first control information belongs, is to be inputted into the first buffer; and first output time information multiplexed for each of at least one or a plurality of the compressed partial audio information and indicating a time on the reproduction time axis of the compressed audio information when the compressed partial audio information, to which the first control information belongs, is to be outputted from the first buffer.
According to this aspect, it is possible to precisely control the inputting and outputting operation for the compressed partial audio information with respect to the first buffer, at the time of reproducing the compressed audio information.
In another aspect of the information recording medium of the present invention, the second control information comprises: second input time information indicating a time on a reproduction time axis of the record information when the divided-compressed audio information, which is included in the information unit together with the second control information, is to be inputted into the second buffer; second output time information indicating a time on the reproduction time axis of the record information when the compressed partial audio information, to which first lead data among lead data each positioned at a lead of one or a plurality of the compressed partial audio information included in the divided-compression audio information included in the information unit together with the second control information belongs, is to be outputted from the second buffer; and third output time information indicating a time on the reproduction time axis of the record information when each of the compressed partial audio information is to be outputted from the first buffer.
According to this aspect, it is possible to precisely control the inputting and outputting operation for the divided-compressed audio information and the compressed partial audio information with respect to the second buffer, at the time of reproducing the compressed audio information.
The above object of the present invention can be also achieved by an information recording apparatus for recording record information onto an information recording medium, the record information comprising a plurality of information units each including header information and divided-compressed audio information obtained by dividing compressed audio information so as to include one or a plurality of lead data positioned at a lead of compressed partial audio information, the compressed partial audio information being generated by variable-length-compressing partial audio information obtained by dividing raw audio information into a plurality of the partial audio information and by multiplexing the variable-length-compressed partial audio information with compression control information, the compressed audio information being generated by arranging the compressed partial audio information in an order of reproduction. The information recording apparatus is provided with: a compressed audio information generating device such as a signal process unit or the like for generating the compressed audio information; a first control information generating device such as a signal process unit or the like for generating first control information to control an inputting and outputting operation of the compressed partial audio information with respect to a first buffer, which is used when reproducing the compressed audio information; a second control information generating device such as a signal process unit or the like for generating second control information to control an inputting and outputting operation of the divided-compressed audio information with respect to a second buffer, which is used when reproducing the compressed audio information; and a recording device such as a mastering device or the like for recording the first control information and the second control information together with the compressed audio information onto the information recording medium after multiplexing the first control information in the compression control information and multiplexing the second control information in the header information.
According to the information recording apparatus of the present invention, since the raw audio information is recorded after it is variable-length-compressed, it is possible to record even the raw audio information, whose reproduction time is long, onto the information recording medium.
Therefore, it is possible to record the audio information of long time duration as compared with a case of recording the non-compressed audio information onto the information recording medium.
Further, since the first control information, which is to control the inputting and outputting operation of the compressed partial audio information with respect the first buffer, is included in the compression control information, and since the second control information, which is to control the inputting and outputting operation of the divided-compressed audio information with respect to the second buffer, is included in the header information, it is possible at the time of reproducing the compressed audio information to easily perform (i) the operation of detecting the compressed audio information from the information recording medium and (ii) the operation of expanding or decompressing the detected compressed audio information by respectively using the first control information and the second control information individually, even if those two operations are performed by individual information reproducing apparatuses, each of which has just one of the first buffer and the second buffer.
Therefore, it is possible to easily promote the cost reduction and the simplification in the structure of the information reproducing apparatus, by performing the detection of the compressed audio information and the decoding process by use of the individual information reproducing apparatuses.
The above object of the present invention can be also achieved by an information reproducing apparatus for reproducing the compressed audio information in accordance with the first control information and the second control information, from the above described information recording medium of the present invention. The information reproducing apparatus is provided with: a detecting device such as an optical pickup or the like for detecting the compressed audio information, the first control information and the second control information respectively from the information recording medium; the first buffer such as a FIFO (First In First Out) memory or the like; the second buffer such as an input buffer or the like; a controlling device such as a system controller or the like for controlling the second buffer to temporarily store and output the divided-compressed audio information in accordance with the detected second control information, and controlling the first buffer to temporarily store and output the compressed partial audio information outputted from the second buffer in accordance with the detected first control information; and a reproducing device such as a core decoder or the like for applying an expanding process corresponding to the compressing process with respect to the compressed-partial audio information outputted from the first buffer to thereby output the partial audio information.
According to the information reproducing apparatus of the present invention, since the raw audio information is recorded after it is variable-length-compressed, it is possible to reproduce even the raw audio information, whose reproduction time is long, from the information recording medium.
Further, since the first control information, which is to control the inputting and outputting operation of the compressed partial audio information with respect the first buffer, is included in the compression control information, and since the second control information, which is to control the inputting and outputting operation of the divided-compressed audio information with respect to the second buffer, is included in the header information, it is possible at the time of reproducing the compressed audio information to easily perform (i) the operation of detecting the compressed audio information from the information recording medium and (ii) the operation of expanding or decompressing the detected compressed audio information by respectively using the first control information and the second control information individually, even if those two operations are performed by individual information reproducing apparatuses, each of which has just one of the first buffer and the second buffer.
Therefore, it is possible to easily promote the cost reduction and the simplification in the structure of the information reproducing apparatus, by performing the detection of the compressed audio information and the decoding process by use of the individual information reproducing apparatuses.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings briefly described below.